Graduation Date

Spring 2025

Document Type

Thesis

Program

Master of Science degree with a major in Natural Resources, option Forestry, Watershed, & Wildland Sciences

Committee Chair Name

Jeffrey Kane

Committee Chair Affiliation

Cal Poly Humboldt Faculty or Staff

Second Committee Member Name

Alan Tepley

Second Committee Member Affiliation

Cal Poly Humboldt Faculty or Staff

Third Committee Member Name

Eric Knapp

Third Committee Member Affiliation

Community Member or Outside Professional

Keywords

Klamath Mountains, Fire ecology, Fuel recovery, Forest recovery, High severity, Stand replacing, Fire, Fuels

Subject Categories

Forestry

Abstract

High-severity wildfires can produce extensive patches of standing dead trees (snags), which later contribute to surface fuel loading and present a hazard as they decay and fall. In the Klamath Mountains of northwestern California and southwestern Oregon, recent increases in the occurrence of large stand-replacing wildfires have raised concerns about fuel and vegetation recovery trajectories, the likelihood of future fires, and resulting impacts to local communities. Nevertheless, the post-fire environment may offer opportunities to enhance ecological and community resilience. Estimates of snag failure and fuel loading can support land management planning and risk assessment following wildfire, though such work is often constrained by the logistical challenges of broad-scale fuel monitoring.

To examine trends in snag failure and surface fuel accumulation following stand-replacing wildfires in the Klamath Mountains, we sampled 73 unmanaged forest plots along a 25-year time-since-fire chronosequence. Snag fragmentation (fallen crown mass) progressed more rapidly than snag fall (whole-tree failure), with smaller trees and hardwoods fragmenting and falling more rapidly. Trends in surface fuel loading were influenced by pre-fire stand conditions, snag failure dynamics, slope, elevation, and aridity. Fine woody fuels peaked approximately 16 years post-fire, coinciding with 95% completion of snag fragmentation. Coarse woody fuels increased throughout the chronosequence, driven by ongoing snag fall. Litter accumulated steadily, while duff loading sharply increased between 10- and 16-years post-fire. Live woody surface fuels, dominated by resprouting hardwoods, reached maximum surface biomass around 17 years post-fire. Fuel recovery trends observed in this study suggest the likelihood of high-severity reburn is greatest during the second decade following fire. Our findings highlight strategic opportunities for meeting fuels management, forest restoration, and public safety objectives.

Citation Style

Elsevier - Harvard

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